1. Field of the Invention
The present invention relates to intravascular prosthesis delivered transvenously for the occlusion of large defects in large hearts. Such defects are mainly atrial septal defects and ventricular septal defects.
2. Description of the Related Art
U.S. Patents: KING et al, U.S. Pat. No. 3,874,388; SIDERIS, U.S. Pat. No. 4,917,089; SIDERIS, U.S. Pat. No. 5,284,488.
Publications: Rashkind--Circulation--vol 67, No. 4, April 1983.
Similar devices have been developed in the last few years for the occlusion of heart defects. They include the KING and MILLS device (U.S. Pat. No. 3,874,388); the SIDERIS button device (U.S. Pat. No. 4,917,089); the "Clamshell" device, which is a variation of the KING and MILLS device; the RASHKIND device; and the SIDERIS adjustable device for the occlusion of cardiac defects (U.S. Pat. No. 5,284,488). The previous devices attempted to occlude heart defects, including patent ductus arteriosus, atrial septal defects, and ventricular septal defects. These devices are used to treat small to moderate heart defects.
There is significant difficulty in occluding large heart defects. Reasons for this difficulty include the absence of adequate rim for the device to seat and the difficulty in positioning on the septum. Attempts at centering have been tried in different designs, while in other designs, like the classical button device (U.S. Pat. No. 4,917,089), emphasis has been given to the maneuverability of the device. In U.S. Pat. No. 5,108,420, MARKS describes an occlusion device which uses a Nitilol wire which has an elongated configuration for passage into the body through a catheter and a preprogrammed configuration which seats on each side of the defect. By pulling the disc through the defect, the inventor claims to achieve centering.
In a similar way, the "Clamshell" device, which in actuality is a modification of the KING and MILLS device (U.S. Pat. No. 3,874,388), attempts to center by pulling the distal disc through the defect, bending it, and then releasing the proximal disc. However, these attempts are only partially addressing the problem and have not been totally successful.
In 1990, a patent was issued for the "Buttoned Device For The Occlusion Of The Intra-cardiac Defects" (U.S. Pat. No. 4,917,089). In 1994, a patent was issued for "Adjustable Devices For The Occlusion of Cardiac Defects" (U.S. Pat. No. 5,284,488). Both devices are useful for the occlusion of heart defects. However, these devices require significant manipulation to position. Also, the devices are not effective in the occlusion of large heart defects. For this reason, the centering button device was designed, aiming at the occlusion of large atrial septal defects and ventricular septal defects which could not be occluded with the previous devices.
For the introduction of the centering buttoned device, the same method as the regular buttoned device and the same release mechanism are used.